Currently, a cellular communications system uses two modes: frequency division duplex (FDD) and time division duplex (TDD). In FDD, reception and transmission are performed on two paired channels that are separated, and an uplink channel and a downlink channel are separated by using a guard band. Therefore, in FDD mode, a terminal device may implement a full-duplex mode to perform reception and transmission in an uplink band and a downlink band simultaneously. In TDD, an uplink channel and a downlink channel are divided by time. Although the uplink channel and the downlink channel use a same frequency, different subframes are used as channel carriers. Therefore, in TDD mode, a terminal device works in half-duplex mode. However, regardless of the FDD mode or TDD mode, within a same frequency or same time, a terminal or a base station is in a receiving or transmitting state only.
Recently, an assumption of single channel full-duplex was proposed by Stanford University, Rice University, and so on. Based on an assumption of receiver self-interference cancellation, this technology cancels interference from a transmitting link to a receiving link, so that data transmission and reception are implemented in a same band. Based on this assumption, a need of paired uplink and downlink bands in the FDD technology may be avoided; a flexible spectrum configuration may be implemented as in TDD; and a problem that only some subframes can be used for uplink or downlink transmission in the TDD technology may be avoided. Therefore, this assumption receives extensive attention in the academic field and industrial field.
Although the single channel full-duplex technology has the foregoing advantages, it is still difficult to apply this technology in a cellular network. Because a full-duplex device requires a large size, the full-duplex technology can hardly be implemented in a user terminal, and may increase implementation complexity and power consumption of the terminal device additionally.